I agree with the earlier suggestions (stay awake until YVR, try to sleep on the way to HKG). However, I find that I usually feel better if I can sleep for an hour or two after arrival (not necessarily immediately, but maybe after a short walk). I find the trip to HKG easier than the trip home - on the way there, it just seems like I've lost a whole day, not that I'm out of sync.

You can try to reset your body clock with daylight cues and melatonin. Close the window shades one you leave YVR and raise them an hour or so before arrival. If you nap on arrival, try to sleep with the curtains open on a bed near the window. Even if you're sleeping, your body will register the daylight and start to adjust. And melatonin works for some - it does for me. I take 2 pills in YVR, sleep comfortably (without getting groggy) and arrive feeling re-adjusted.